The statements in this section merely provide background information related to the present disclosure and should not be construed as constituting prior art.
Vehicles adapted for mobility-challenged individuals are necessary in order to provide these individuals with the ability to reach locations requiring vehicular travel. These vehicles often have electrical or hydraulic powered wheelchair lifts for assisting wheelchair occupants both enter and exit the vehicle. Parallelogram-type wheelchair lifts are offered by a number of manufacturers, including the L900 series of lifts from The Braun Corporation of Winamac, Ind. (see, for instance, U.S. Pat. No. 5,261,779—the disclosure of which is incorporated in its entirety herein by this reference). These lifts employ various mechanisms to cause the platform to move arcuately upward from the horizontal transfer level to a vertical or over-vertical stowage position.
One system involves the use of an articulated lever assembly comprising a pair of arms of unequal length pivotably connected to each other at one end, and pivotably connected at their other respective ends to a vertical lift arm end link (the bottom end of which is pivotally secured to the platform) and an inboard end of the platform. As the hydraulic ram of the lifting assembly is actuated, thereby lifting the platform from the ground level toward the transfer level, a sliding block, which is pivotally secured at the common center of the two arms, comes into contact with the lower arm of the parallelogram. As the lifting continues, and the end link approaches the lower arm, the lower (longer) arm of the lever assembly is pushed downwardly. In turn, this causes the outboard end of platform to rotate upwardly to the stowed position.
Since parallelogram-style lifts must be able to stop at various positions throughout their lifting cycle, it is important that their operation be smooth and efficient and with minimal unwanted drift, jerkiness and/or misalignment problems. The present teachings are intended to improve upon and resolve some of these known deficiencies of the art.